1. Field of the Invention
The present invention relates to a system and method for monitoring a receiving portion in a wireless base station system and to a recording medium on which a monitoring program is recorded. More particularly, the present invention relates to a system and method for monitoring a receiving portion in a wireless base station system which performs communication with mobile terminals and to a recording medium on which a monitoring program is recorded.
2. Description of the Prior Art
In wireless base station systems, measurements relating to a wireless level diagram are made. In particular, when a noise figure (NF), gain, and feeder loss of an outdoor receiver amplifier are actually measured, there is a need to move measuring devices to the measurement places. On the other hand, desktop measurements are made in such a manner that a feeder loss is obtained from a feeder length and a determination is made by a theoretical process as to whether the total NF is appropriate in terms of wideband code division multiple access (WCDMA) system, and the determination result is verified with the above-mentioned actual device. A difference between NF characteristics which occurs in a case where the outdoor receiver amplifier is configured for a multivendor service is multiplied by an offset according to station data or the like to form a WCDMA system parameter.
However, with the process including moving measuring devices to measurement places, there is a disadvantage that it is necessary to perform operations in dangerous places, e.g., a place immediately below an antenna in the case of measurement of an outdoor receiver amplifier. There is also a disadvantage that troublesome operations for computing feeder loss, a total NF, etc., are required.
Systems for the above-described kind of receiving portion monitoring are disclosed in Japanese Patent Laid-Open No. 9-200069 (hereinafter referred to as related art document 1) and No. 11-186956 (hereinafter referred to as related art document 2) and Japanese Patent Publication No. 2503889 (hereinafter referred to as related art document 3).
The technique disclosed in the related art document 1 relates to a device for detecting a fault in a high-sensitivity wireless portion installed outside a building. A detection of a fault in an outdoor receiver is performed by making determination using monitoring means 35 as to whether a pilot signal level is lower than a reference value. The invention disclosed in this document, however, differs from the present invention in that it does not use the bit error rate (BER) as a determination criterion.
The technique disclosed in the related art document 2 uses means for detecting a fading pitch from a reception signal, BER detection means, received input level measuring means in a mobile wireless portion, and appropriate moving speed detection means for deriving a current appropriate moving speed from fading pitch detection information, BER, and received input level information. This technique enables a user to reduce a deterioration in communication quality due to fading by considering the derived moving speed. However, the invention disclosed in this document differs from the present invention in that it is concerned with a mobile wireless portion and aims to reduce deterioration in communication quality due to fading.
The technique disclosed in the related art document 3 relates to a device for detecting a fault in a receiver amplifier installed outside a building and makes fault determination by preparing a fault detection reference value from a standard attenuation value relating to leakage of a transmitted signal from a transmitter to a receiving circuit in an antenna-sharing unit, a standard amplification value of the receiver amplifier, and transmission power information of the transmitter, and by comparing electric field intensity information output from an electric field detecting portion with the reference value. The invention disclosed in this document differs from the present invention in that it uses no pilot signal.